1. Field of the Invention
This invention relates to a small-sized electric motor used for, for example, driving a window glass up and down in a power window system of an automotive vehicle.
2. Description of the Prior Art
Heretofore, there has been used a small-sized electric motor as a motor suitable for the aforementioned purpose, for example, which has structure shown in FIG. 8 and FIG. 9.
In a small-sized electric motor 100 shown in the figures, an armature 102 is housed in a motor case 101 forming a part of a housing, and the motor case 101 is connected with a gear case 104 housed with reduction gears 103 and forming another part of the housing at an opening 101a thereof.
A commutator 102a of the armature 102 is in contact with brushes (not shown) and the brushes are connected with power terminals 105 and 106, respectively.
The power terminals 105 and 106 protrude toward the gear case 104 in the rightward direction from an end bracket 104a provided on the left side of the gear case 104 as shown in FIG. 8, and the power terminals 105 and 106 are connected with a connector 109.
The connector 109 is provided, as shown in FIG. 9, with socket terminals 110 and 111 connected to ends of lead wires 107 and 108, respectively. By pressing the connector 109 toward the power terminals 105 and 106 from the right side in FIG. 8 until the end face 109a of the connector 109 comes in contact with the end bracket 104a, the socket terminals 110 and 111 are fitted onto the respective power terminals 105 and 106 in the horizontal direction as shown in FIG. 8, whereby they are connected electrically with each other.
Furthermore, the lead wires 107 and 108 are secured to the gear case 104 through a clamp 112 screwed on the gear case 109 at the middle part thereof.
By supplying electric power to an armature coil of the armature 102 through the lead wires 107 and 108, the socket terminals 110 and 111, the power terminals 105 and 106, the brushes and the commutator 102a, the armature 102 rotates in either direction according to the current direction.
In the above-mentioned conventional small-sized electric motor 100, it is necessary to provide open space sufficient to insert the power terminals 105 and 106 into the socket terminals 110 and 111 in the connector 109 since the electric motor 100 is so structured that the power terminals 105 and 106 are connected with the socket terminals 110 and 111 by pressing the connector 109 toward the end bracket 104a in the horizontal direction and inserting the power terminals 105 and 106 into the socket terminals 110 and 111.
However, it is not always easy to provide a sufficiently wide space in the vicinity of the end bracket 104a disposed with the power terminals 105 and 106 because the small-sized motor 100 is designed considering miniaturization preferentially in most cases. Therefore, it is difficult to fit the connector 109 onto the power terminals 105 and 106 and there is a problem in that it is impossible to improve the work efficiency in the assembly process of the motor 100.
Furthermore, because the lead wires 107 and 108 connected with the respective socket terminals 110 and 111 are secured to the gear case 104 through the clamp 112, it is not only necessary to keep a large number of parts in stock inclusive of the clamp 112 and the screw to fix the clamp 112 on the gear case 104, but also necessary to shift the clamp 112 into another position in order to turn the direction of the lead wires 107 and 108 to the left side from the right side in FIG. 8.
Accordingly, there are other problems in that the total man-hours required to assemble the motor 100 increase owing to the low work efficiency, and cost of the parts increases remarkably.
In addition to above, there is another problem since there is the possibility that the connector 109 is disconnected from the gear case 104 when external force is applied on the connector 109, because the connector 109 is fitted to the gear case 104 by merely inserting the power terminals 105 and 106 into the socket terminals 110 and 111 in the connector 109.